Abstract:Three bamboo floras of East China were investigated in Tianmushan Mountains (on the border between Zhejiang and Anhui Provinces), Huangshan Mountains (in the south of Anhui), and Dabieshan Mountains (in the border area of Henan, Hubei and Anhui Provinces), which include 10 genera with 75 species, 8 genera 49 species, and 7 genera 30 species, respectively. Areal type analysis of genus and species elements indicates that the bamboo floras in three mountains are markedly subtropical in nature and can be recognized as important part of bamboo flora of East China, however, the flora of Dabieshan Mountains reveals a transitional character having certain amount of elements of Central China. Based on a priliminary inference made from geologic history, modem distribution pattern of bamboos and principle of historical phytogeography, the bamboo floras of Tianmushan Mountains and Huangshan Mountains originated not later than the Eocene epoch of the Paleogene period, and earlier than that for Dabieshan Mountains. Most of the species of genera Phyllostachys and Brachystachyum, with primitive taxa, have been found in Tianmushan Mountains where geochronology is quite age-old and relatively stable in geological structure, which shows the mountains can be considered as differentiation centre and possible origin centre of these two genera. phyllostachys extended it distribution sea radially from the origin caster to subtropical China, while Brachystachyum had four distribution routes: the east route ran to E aid SE Zhejiang, the south to the a part of Nanling Mountains, the west to Jiangxi, aid the north to E Anhui The relationships among the three bamboo floras are discussed.

Abstract:Rhizobium resources of legumes were investigated in 29 counties in Fujian Province. Two hundred and seventy-eight nodule samples belonging to 63 legume species in 36 genera were collected. Root nodules are diverse in morphology and light yellow or pink in colors, and the size of root nodules ranging from 1 to 10 mm in the general condition. Nitrogenase activities in nodules measured by acetylene reduction method were 1 to 24 μmol C₂H₄ g^-1 fresh nodule h^-1 for most nodule samples,the highest being 87.2929 μ mol C₂H₄ g^-1 fresh nodule h^-1 in species Podocarpium podocarpum var. oxyphyllum. There were 228 rhizobial strains isolated from nodule samples, 155 strains of which were reinoculated to the corresponding host legumes, and 138 strains were nodulated , the nodulation rate being 89.0%.

Abstract:A phytoplankton and water quality survey was conducted in flood and dry seasons in 2000 in 19 typical reservoirs in Guangdong Province, China, in order to evaluate the trophic state and blue-green algae (cyanophyty) pollution. Results showed that many reservoirs were polluted by blue-green algae, of which the potentially toxic Microcystis was the dominant species and often took up over 50% of the total phytoplankton cell concentration. Cell density and percentage proportion of blue-green algae were 0.1×10⁴-6728.4×10⁴ cells L^-1 and 0.53%-99.2%, respectively. Furthermore, species richness and density of blue-green algae were closely related to the water quality. Results based on phytoplankton community structure and trophic state index(TSI) revealed that the trophic level was lower in reservoirs located at upper reaches of rivers and mountainous districts than at lower reaches and coastal regions. Moreover, the water quality of reservoirs in Dongjiang and Beijiang drainage areas were better than those in other water areas especially the west coastal area and the delta area of the Pearl River. Most reservoirs have been polluted to some extent and belonged to mesotrophic state, two in Dongjiang drainage area are oligotrophic, while other three which located in highly economic developing coastal areas are heavily polluted and enriched.

Abstract:Laboratory leaching experiment and UV-visible spectra determination were carried out for leachates from fresh litter fall and litters in F (fragmented) and H (Humus) layers in 35-year-old plantations of Castanopsis kawakamii and China fir (Cunninghamia lanceolata) in Fujian Province. The results showed that the concentration of dissolved organic carbon (DOC) in leachate from fresh litter fall was lower and that from F layer was higher for both plantations. In Castanopsis plantation, DOC concentration declined with the increasing number of leaching times, whereas that in China fir plantation increased at first then decreased. UV-visible spectra absorption values of leachates from litter fall and different litter layers decreased with the increase of wavelength, and a peak at about 200 nm was observed in all cases. E₂₄₀/E₄₂₀ ratio of dissolved organic matter from different sources was quite different. The concentration of DOC in leachates from the same sample was linearly correlated with E₂₀₀ (R²>0.90), suggesting that DOC concentration could be estimated at E₂₀₀.

Abstract:The differentiation of ovule primordium of a hybrid of Phalaenopsis initiated at low temperature (12-18℃) 50 days after pollination, and megasporogenesis appeared 60 days after pollination. The megasporogenesis at normal temperature (20-25℃) was delayed for 10-15 days. Although the megagametophyte formed and even the double fertilization had been finished 70 days after pollination at normal temperature, the megasporogenesis had not yet been finished at low temperature. Nucellar cells degenerated in advance under low temperature, which resulted in thickened embryo sac wall surrounding the megasporocyte. The embryo sac developed into functional megaspores only and no mature embryo sac was generated.

Abstract:Leaf venation of all the 20 species of Caesalpinia occurring in China were studied. Venation patterns of the leaflets in the genus studied are all brochidodromous. The secondary veins are abruptly curved. The highest vein order is quaternary or quinternary. Veinlets are simple, or once or twice branched. Leaf venation characters show that both Caesalpinia s.s. and Mezoneurum are in a natural group. A key to the species of Caesalpinia based on leaf venation characters is presented.

Abstract:The DNA was isolated from banana grown in Guangzhou, which was infected with bunchy top virus. 1.1 kb DNA of replicase of banana bunchy top virus (BBTV) was obtained by PCR using this virus DNA astemplates for amplification. The derived DNA of the BBTV replicase was encoded by the C-Terminal of BBTV. It was homologous to 90% with the Australian BBTV. The reformed BBTV replicase was cloned to pBI 121 in the position between CaMV 35S promoter and NOS termination sequence, and a plant expressed carrier was established. Four transgenic platelets with BBTV replicase gene in T₀ generation were detected by PCR and Western blot analysis. The ability of these transgenic banana against bunchy top virus is being investigated.

Abstract:The changes in light energy dissipation and xanthophyll cycle components in super-high yielding rice (Oryza sativa L.) cv. Peiai 64S/E32 were compared with those in traditional hybrid Shanyou 63 during the senescence of flag leaves in the field. The results showed that the maximum photochemical efficiency of PSII (F_v/F_m), quantum efficiency of PSII (ΦPSII), photochemical quenching coefficient (qP) and photosynthetic rate all decreased with the senescence of flag leaves, but the non-photochemical quenching coefficient (NPQ), the pool size of xanthophyll cycle (Z+A+V) and deepoxidation state (DES) increased. There was no significant difference in ΦPSII and qP between super-high yielding rice Peiai 64S/E32 and traditional hybrid Shanyou 63 on the 55-75 day after transplanting, but the decreases in ΦPSII and qP in Peiai 64S/E32 were less than those in Shanyou 63 after transplanting for 75 days. This suggests that there is a better PSII function for utilization of the absorbed light energy in Peiai 645/E32 than in Shanyou 63 during the senescence of flag leaves.

Abstract:New buds obtained by dark culture from the rhizomes of ten species or cultivars and hybrids of Heliconia were used as explants which were cultured on MS medium supplemented with 2-10 mg L^-1 BA and 0.2-1.0 mg L^-1 NAA. The experiments showed that the explants could induce shoots and proliferate. Best result for rooting was observed on MS medium supplemented with 0.5 mg L^-1 NAA plus 0.5% active carbon. The plantlets transferred to pots containing sand/turf mixture (1:1), or sand/perlite (1:1), or sand only showed a survival rate more than 90%.

Abstract:Western blot showed that binding protein(BiP) kept a high expression level during maize embryo development, which coincided with the change in embryo soluble protein. The content of soluble protein rapidly increased with the embryo development after pollination for 16 days, while BiP markedly increased from 22^nd day after pollination. The BiP failed to respond to heat shock. Immunohistochemical localization showed that BiP localized in plumule, primary vascular tissue and aleurone layer during embryo development.

Abstract:Yambean (Pachyrhizus erosus (L.) Urban) seeds were stored in drier in refrigerator at 4℃, in sealed drier containing saturated solution of potassium sulfocyanate at 15℃ and at 45% relative humidity, in room temperature, and in ambient temperature after the seeds were dried at 6.43% seed moisture (ultra-dry treatment). The experiments showed that the germination rate of yambean seeds declined to 50% in room temperature after 12 months of storage, and completely lost the germination capacity after 24 months.

Abstract:In the investigation of vegetation with invasive weed Mikania micrantha, 81 sample plots with10 m×10 m each were used to study the plant species, breast height diameter, crown diameter, slope and aspect, and the importance value of each species. The corresponding data obtained from original or secondary forest vegetation were used for comparison. Ecological-economic loss was analysed by methods of market valuations, shadow engineering, opportunity cost, and substitute expense. It is estimated that the economic loss amounts to 4.5-10.13 million yuan for the whole island.

Abstract:tropical montane rain forest was investigated in Mengsong, south-west to Jinghong City ofXishuangbanna region in the south of Yunnan near the border between China and Myanmar. There are 623 species of seed plants belonging to 327 genera and 116 families in this forest. Analysis of areal types shows that 32.8% of the families are of tropical and subtropical type, 23.3% tropical to temperate type, and 18.1% typically tropical type. Areal types at generic level mostly are tropical (81.4%), in which 28.4% are of Indo-Malaysian type and 26.8% are of pantropic type. The ratio of tropical to temperate genera is 258:55. As for specific rank, the elements of tropical Asia type reaches 65.0%, and that of endemic to China 26.5%. The number of tropical species (431 species) is far more than the temperate ones (18 species). It is concluded that this flora is tropical in nature with obvious characteristics of Indo-Malaysia flora. It is a transitional area of tropics to subtropics, and is the north distribution limits for many typically tropical plants.

Abstract:An intergeneric graft chimera between Citrus reticulata 'Ponkan' and Poncirus trifoliata (L.) Raf. was found in a farmholding orchard in Juxi Town, Liancheng County, Fujian Province, in 1986, which was obtained from the buds appeared after freezing damage in graft union of 2-year-old seedling of cultivar 'Ponkan' grafted on the stock of Poncirus. The graft chimera is named as + Citroponcirus 'Hormish'which has unifoliate, bifoliolate and trifoliolate leaves in some branches, and trifoliolate in other branches, showing a chimera of the two species. Young fruits are pubescent as those in Poncirus. Mature fruits are similar to 'Ponkan' in shape and in flavour, but some have the appearance of chimera character of both Poncirus and 'Ponkan'. Juicy pulp is mostly orange-red in colour with a few yellowish pulp. This report aims to give and disscuss the name of this chimera which is unique in Rutaceae.

Abstract:Biological invasion and its effects on ecosystem and biodiversity are very important components of the global change, and have been paid great attention worldwide. The impact of invasive plant species on natural ecosystem and biodiversity is becoming more and more serious, which even leads to irreversible species extinction and ecosystem collapse. This is a review of recent studies on the relationship between fire and invasive plant species. This subject is very complicated, which is affected by the characteristics of exotic species, the time, frequency and intensity of fire, and other factors. Sometimes, fire can suppress or inhibit the growth and establishment of exotic species, and sometimes it can facilitate spreading and invasion of exotic species by reducing interference from native species. On the other hand, biological invasions alter the structure and function of ecosystems in myriad ways, and many of the alterations influence fire regimes and post-fire response. Some invasive plants can promote the fire frequency or intensity by changing fuel and fire regimes, and some species is fire suppressor. The characteristics of exotic species and the invasion mechanisms are so diverse that no common pattern could explain all cases. So prevention and management of invasive species is a hard and complicated job, which needs research and consideration on biological features of invasive species and native species, ecosystems, and other environmental factors. As one of the management method of invasive species, fire can be used to control some invasive species effectively when managed scientifically.

Abstract:A review of research works on artemisinin production is presented under the following headings: 1.cultivation of Artemisia annua including cultivation practices, plant breeding, harvesting time, processing and preservation； 2. artemisinin production by plant tissue culture； 3. biosynthesis of artemisinin, and 4. perspective.